1. Field of the Invention
The present invention relates to small electric devices having input and output terminal sections, such as a photoelectric switch, and more particularly to a terminal connector of small electric devices, which has a simplified construction of connecting external lines with terminals in a substrate having internal circuits and therefore making an easy assembling of the devices possible.
2. Description of the Related Art
Generally, when connecting an electric wire 60 to a small electric device, a metal terminal member 61, as shown in FIG. 4, is fitted on an end of the electric wire 60 and the terminal member 61 is fastened to the terminal holder of the electric device. The terminal holder includes a terminal plate and a terminal screw to be fitted in the terminal plate, and in the situation that the terminal screw 62 is removed temporarily from the terminal plate, the terminal member 61 is arranged on the terminal plate and the terminal screw 62 is inserted through the hole of the terminal member 61, thereby fastening the terminal member 61 to the terminal plate. To remove the terminal screw 62 from the terminal plate whenever the terminal member is fastened to the terminal holder as just described has the disadvantage of not only complicating the operation but also causing the loss of the terminal screw.
To eliminate the above disadvantages, the applicant has invented a terminal connecting device of the type in which a terminal screw is movably arranged with respect to the corresponding terminal plate and moreover the terminal screw is made stationary with a gap formed between it and the terminal plate as disclosed in U.S. Pat. Nos. 4,519,668 and 4,542,953. With the terminal connecting device constructed as described, when fastening a terminal member at the end of an electric wire to a terminal holder, with a terminal screw held stationary so as to form a gap between it and a terminal plate, the terminal member is arranged on the terminal plate and in this condition the terminal screw is moved, thereby eliminating the need to completely remove the terminal screw from the terminal plate, simplifying the fastening operation of the terminal member and preventing the terminal screw from being lost.
Incidentally, there have been no conventional electric devices which have given consideration to a construction for connecting simply the terminal connecting device to a circuit substrate on which all of the electric circuits of the electric devices are mounted. Thus, when fastening the terminal connecting device to the electric devices, special wirings are required for providing electric connections between the terminal connecting device and the substrate or a part of a terminal plate forming the terminal portion of the terminal connecting device has been elongated to contact with a terminal on the substrate. Therefore, these constructions have produced disadvantages in that the former complicates the assembling operation of an electric device and the latter increases the production cost of the components.